1Drop your ICO icons into the box above, or pick them from your device — there is nothing to install and no account to create.
2Choose how hard to squeeze: a quality or bitrate target, and optionally smaller dimensions if size matters more to you than detail.
3Start the job and let the workers re-pack the file; your original is never modified in place.
4Compare the new size against the original, then download the compressed ICO file.
Compress ICO FAQ
Does the format of my file change how much I can save?
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Very much so. ICO is a container that holds several square bitmaps at once (16, 32, 48, 64, 128 and 256 px) so Windows and browsers can pick the size they need. That determines both the headroom available and whether the saving costs you anything in fidelity.
Is there anything specific to ICO I should know before compressing?
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Yes — an ICO is a stack of square bitmaps, not one image, so operations apply to the stack and Windows still picks whichever size it wants. It is worth knowing before you overwrite an original you might need again.
What is the most common mistake when compressing ICO icons?
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Compressing the same file repeatedly. Each pass on a lossy format is a fresh generation of loss and the savings shrink while the damage accumulates. Go from the original to your target in one step, and keep the original.
What do I get back, and can I control the trade-off?
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A single compressed file per input, at a quality or bitrate level you choose rather than a fixed default. If the result is not small enough, changing the dimensions or the duration will do more than pushing the quality slider further down.
Can I run Compress ICO on several ICO icons at once?
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Yes. Icon files are tiny, so a batch of them completes almost instantly; the round trip is dominated by the upload, not the processing.
Which sizes should the icon contain?
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16, 32 and 48 pixels cover Windows Explorer and browser tabs; 256 covers large-icon view and modern shortcuts. Keeping all of them in one file costs almost nothing and stops the operating system from having to guess.
Does Compress ICO cost anything?
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No. Compress ICO is free with no account, and the output carries no watermark — which matters more here than anywhere else, since an icon is a handful of pixels with nowhere to hide one.
Is there a file size limit on Compress ICO?
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Yes: free accounts process images up to 5 MB each, which no icon file will ever approach — a full 16-to-256-pixel stack is typically well under 200 KB. Icons are the one part of the image family where the cap is genuinely irrelevant.
Why does a PNG site host Compress ICO?
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PNG.to is built around the format you use when you cannot afford to lose a pixel: lossless, alpha-capable, and the correct answer for screenshots, logos, line art and anything with hard edges. Image work is rarely one step: people arrive to change a format and leave needing the picture a different size, a different weight or a different shape. Running Compress ICO on the same upload pipeline, the same size caps and the same account is the whole reason it is here rather than on a fourth tab.
What should I do with the result once Compress ICO is finished?
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The converter on this site moves images to and from PNG, JPG, WebP, GIF and SVG — which is the step where the decision about transparency actually gets made. That is the step most people actually came for, and doing it after Compress ICO rather than before it means the conversion works from the file you finally settled on.
Is Compress ICO here the same tool the sibling sites run?
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The engines are shared — the same libraries, the same workers, the same limits. What differs is the advice, and the advice here starts from one fact about the format this site is named after: there is no quality slider to get wrong — a PNG round-trips bit-exactly, so the only thing edits cost you is file size. A PNG site is opinionated about where PNG is the right destination and where it is not, and that judgement is worth more than the button.
Do I need an account, and does anything get kept?
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No account, and nothing is kept: uploads are deleted from the workers shortly after the job finishes, and nothing you process is indexed, listed or used for anything else. Free accounts exist for history and batch size, not for access.
